The red cabbage plant changes its colour according to the pH value of the soil. In acidic soils, the leaves grow more reddish while an alkaline soil will produce rather greenish-yellow coloured cabbages. The juice of red cabbage can be used as a home-made pH indicator, turning red in acid and blue in basic solutions. Red Cabbage is dark red outside with a red and white interior. Its colour make it an attractive addition to stirfries and coleslaws .When cooked red cabbage will turn blue unless vinegar, acidic fruit or another acidic ingredient is added during cooking. Available all year round with peak season being autumn.